Production of Light Olefins

Process Operated by Feeds Products Catalyst Conditions 

Phillips Triolefin Process Phillips ran from 1966-1972 propylene 15 kt/a ethylene-l-30 kt/a 2-butene WOg/SiOz 400°C 

Reverse Triolefin Process Lyondell Petrochemical Co. operated since 1985 ethylene-h 2-butene 136 kt/a propylene WOs/SiOz 400°C 

ABB Lummus OCT BASF Fine Petrochemicals in progress Mitsui Chemicals in progress Korea Petrochemical Co. in progress ethylene-h 2-butene ethylene-h 2-butene ethylene-H 2-butene 400 kt/a propylene 140 kt/a propylene 110 kt/a propylene WOg/SiOz 350°C 20 bar 

Axens Meta-4 Not yet commercialized ethylene-H 2-butene propylene Re207/Al203 35°C 60 bar 

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A major use of propane recovered from natural gas is the production of light olefins by steam cracking processes. However, more chemicals can be obtained directly from propane by reaction with other reagents than from ethane. This may be attributed to the relatively higher reactivity of propane than ethane due to presence of two secondary hydrogens, which are easily substituted. 

Adding ZSM-5 catalyst additive is another process available to tlie refiner to boost production of light olefins. ZSM-5 at a typical concentration of 0.5 to 3.0 wt% is used in a number of FCC units to increase the gasoline octane and light olefins. As part of the cracking of low octane components in the gasoline, ZSM-5 also makes C. C4, and Cj olefins (see Figure 6-2). Paraffinic feedstocks respond the most to ZSM 5 catalyst additive.. 

Increasing use of feed segregation to maximize production of light olefins. 

Correlations presented in the middle thirties enabled the prediction of octane number improvement resulting from thermal reforming (7, 21). They have continued to appear in the literature (6, 20). Improvement of the octane number of naphthas has been the principal function of thermal reforming, but Egloff (8) discusses its usefulness also for the production of light olefins which provide feed stocks for alkylation or polymerization processes. To show the distinct improvement in the yield-octane relationship realized by the catalytic polymerization of C3 and C4 olefins produced by thermal reforming, Mase and Turner (16) present experimental data at various reforming severities for two naphthas. 

Centi G, Iaquaniello G, Perathoner S. Can we afford to waste carbon dioxide Carbon doxide as a valuable source of carbon for the production of light olefins. ChemSusChem. 2011 4 1265-73. 

Production of light olefins (propylene, n-butenes and isobutene) will be one of the main targets of FCC untis in the near future. These olefins can be fed to alkylation and etherification units to produce additional high octane environmentally acceptable gasoline components, or used as petrochemical feedstock. Johnson and Avidan (85) used higher amounts of ZSM-5 (10-20%) to increase the production of light olefins, mainly propylene. 

For the most part we are concerned with acid catalysed reactions in which carbonium ions are the key intermediates. Carbonium ions are formed by the interaction of a feed molecule with an acid site on a catalyst surface. Carbonium ion chemistry is well defined and has several features relevant to the production of light olefins. These are illustrated in Figure 2.6. 

Besides faujasite (Y) zeolites, today s catalysts contain several additional functional materials, such as metal traps, nickel-resistant matrices, bottoms-cracking matrices, and small pore zeolites, such as, for instance, ZSM-5. These zeolites are often added as separate (additive) particles with the intention of boosting the gasoline octanes and/or the production of light olefins (propylene). 

Long-chain paraffins are both valuable and highly prone to cracking. Therefore, to maintain high selectivity and yield, it is necessary to operate at relatively mild conditions, typically below 500""C, and at relatively low per-pass conversions. While this is economical for the production of heavy linear olefins, it is not for the production of light olefins. 

Production of light olefins by the catalytic dehydrogenation of light paraffins must be able to maintain reasonable per-pass conversion levels and high olefin selectivity. Very importantly, it must be able to produce olefins in high yields over long periods of time without shutdowns. 

Catalytic dehydrogenation of paraffins and of ethylbenzene is a commercial reality in numerous applications, from the production of light olefins, heavy olefins, to that of alkenylaromatics. Oxydehydrogenation, on the other hand, is still in the developmental stage, but, if successful, holds great promise on account of its potential energy savings. 

Gould, R. M., Avidan, A. A., Soto, J. L., Chang, C. D. and Socha, R. F., "Scale-up of a Fluid-bed Process for Production of Light Olefins from Methanol", paper presented at the AIChE National Mtg., New Orleans, LA, April 6-10, 1986. 

Whereas the cracking reaction rate becomes significant above 700°C, dehydrogenations only take place substantially above 800 to 850°C. Moreover, the processes of the formation of polyaromatic hydrocarbons and coke only occur rapidly at temperatures above 900 to 1000°C. The adoption of long residence times or the elevation of the reaction temperatures hence favor the reaction yielding heavy aromatic derivatives at the expense of the production of light olefins by cracking. 

FCC although it is not likely that the Y-type zeolite will be replaced as principal active agent, there may be room for additives enabling selective production of light olefins ranging from propylene to pentenes as long as these additives are competitive with the ZSM-5 regarding costs, activity and stability. 

When methanol is reacted on HZSM-5 zeolites, and hydrogen transfer and cyclization is avoided, then instead of producing aromatic gasoline, the process is directed to the production of light olefins (213,214). Different 8 MR zeolites (215,216) have been used to convert methanol to olefins and the results obtained (217) are compared in Table 13 with those obtained with ZSM-5 zeolite. 

Huang WW, Gong FY, Fan MH, Zhai Q, Hong CG, Li QX (2012) Production of light olefins by catalytic conversion of lignocellulosic biomass with HZSM-5 zeolite impregnated with 6 wt.% lanthanum. Bioresour Technol 121 248... 

Apart from the oxidation of organic molecules, the catalytic pyrolysis of waste tires to light olefins using mesoporous material containing metals was also performed. Generally, the production of light olefins has been derived mostly from steam crackers and refinery fluid catalytic cracking units. Moreover, their demand... 

Wang C, Pan X, Bao X. Direct production of light olefins from syngas over a carbon nanotube confined iron catalyst. Chin Sci Bull 2010 55 1117-9. 

Cavani, F. and Trifiro, F. (1995). The Oxidative Dehydrogenation of Ethane and Propane as an Alternative Way for the Production of Light Olefins, Catal. Today, 24, pp. 307-313. 

ZSM-5 (increases octane and production of light olefins) R (promotes combustion of CO to CO2 in regenerator)... 

A new catalytic material has been developed which reduces the activation energy required, thus allowing the reaction to be carried out at a significantly lower temperature compared with that required for steam cracking, and also favors the production of light olefins. 

Although the MTG process is an excellent process for gasoline production, it is possible to modify the product distribution to obtain a higher yield of olehns or aromatics. To enhance the production of light olefins, the following strategy has been applied. 

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